CONTROL PROPERTIES OF AGED HUMAN MOTOR UNITS

描述：（研究者摘要）本提案的目的是 以确定老年人使用什么策略来控制运动神经元放电。 首席研究员的初步工作表明， 可以使用替代方案来控制运动神经元。 比如说， 运动单位的异常去募集行为， 运动单位的放电和不寻常的双重放电的发生， 被观察到。 此外，其他实验室的工作表明， 尽管需要保持力量和精度， 日常运动。 提出实验以解决以下关键问题 问题：1）老年人使用什么策略来激活运动单位 在随意的肌肉收缩中 2)协同和拮抗 老年人的肌肉会采取不同的运动策略吗？ 3)老年人使用什么样的运动单位控制策略来应对 突然失去平衡 本提案中所述的实验 将在年轻人和老年人中进行，使用第一背 骨间肌群和胫前肌群在随意用力时 达到100%的最大随意力量。 放电 单运动单位将使用专门的四股 针电极和计算机辅助技术来分解复合物 将信号发送到各个发动机单元的发射列中。 长期目标是 确定是否使用替代的电机控制策略来维持 老年人的最佳运动活动。

DESCRIPTION: (Investigator's Abstract) The objective of this proposal is to determine what strategies aged adults use to control motorneuron firing. Preliminary work by the Principal Investigator suggests that the elderly may use alternative schemes for controlling motorneurons. For example, unusual derecruitment behavior of motor units, increased synchronization in the firing of motor units and unusual occurrence of doublet firing have been observed. In addition, work from other laboratories has shown loss of motor units with age despite the need to maintain force and precision in daily movements. Experiments are proposed to address the following key questions: 1) What strategies do older adults use to activate motor units during voluntary muscle contraction? 2) Do synergistic and antagonistic muscles adopt alternative strategies for motor action in older individuals? 3) What motor unit control strategies do older adults use to respond to sudden distrubances in balance? The experiments described in this proposal will be conducted in young and old adults using the first dorsal interosseous and anterior tibialis muscle groups during voluntary effort ranging up to 100 percent of maximal voluntary strength. Discharges of single motor units will be recognized using a specialized quadrifilar needle electrode and a computer aided technique to decompose the composite signal into individual motor unit firing trains. The long term goal is to determine whether an alternative motor control strategy is used to maintain optimal motor activity in the elderly.